Information about the Mega Bridge Rio Antirio

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Acknowledgement
All praise is to Allah, The Lord of The Creation. Certainly Almighty Allah gave us
the strength & courage to make this report.
We are grateful to our teacher Miss Sultana, who gave us the opportunity to
implement our skills in making a report which surely was a great experience.

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TABLE OF CONTENTS
 Introduction 3
 Name 4
 Location 4
 Concept, Design and Construction 5
 Main Bridge Concepts 6
 Pylon 6
 Deck 8
 Construction and Completion 8
 Trouble with Cable Links 9
 Monitoring System 9
 Records 10
 Conclusion 11
 Bibliography 12

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Introduction
The Gulf of CorinthinGreece isdeep,wide andlong.Greatattributesformarine trafficbuta nightmare
for those travellingbyland.The Gulf of CorinthvirtuallychopsGreece intwo.The onlylandroute
betweensouthernGreece andthe WesternEurope is240 kmeast.Bridgingthe Gulf is beenagoal more
than a centurybut itis neverbeenpossibleuntil now.
The water istoo deep,the seabedtoosoftand an earthquake faultline comes inthe middle. Challenges
of buildingbridge here weremindboggling.The biggestproblemwasEarthquake.Bridgeshave been
builtinthe earthquake zone before,butthisbridge hadtocross an active faultline.Ontopof that the
waterhere isextremelydeepi.e.60 meters.Nootherbridge hasbeenbuiltwithfoundationslikethat.
In April 1996 the onlyway to crossThe Gulf of Corinthwasby meansof Ferryboat. Ina perfectweather
the journeywouldtake 45 minutes,a bridge will reduce thattofive. SofordecadesThe Greece
Governmenthasbeenlookingfornewbridge designs,the bridge will have tobe extraordinary.The
Designof the bridge looksverysimple.368 steel cables,4conical towersanda yellow ribbonof roadway
that glowsat night.

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Mega Structure – Rio Antirio Bridge
Name
Its official name isthe CharilaosTrikoupisBridge. CharilaosTrikoupis wasa19th century Greekprime
minister,andsuggestedthe ideaof buildingabridge betweenRionandAntirion;however,the
endeavourwastoo expensive atthe time,whenGreece wastryingtogeta late footintothe Industrial
Revolution.
Location
The 2,880 m (9,449 ft) longbridge islocatedinGreece andit joinssouthernGreece tothe Western
Europe,makingthe journeyasshortas 5 minuteswhichusedtobe 45 minutesina ferryor viathe
isthmusof Corinth at itsextreme eastend.

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Concept, Design, and Construction
All Bridge designsare basedonfourtypes:
Beam Bridges:
The longestbridgesinthe worldare beambridgesbutitwouldn’tworkhere because itwill blockthe
wayof shiptraffic.
Arch Bridges:
An Archbridge can stay clearof huge shiptrafficbuta span of Gulf Corinthwill require 4timesbigger
than anyarch bridge builtbefore.Thisdesignwastoorisky
Suspension Bridges:
A suspensionbridge canbe of longest distances,butsuspensionbridgesare tooexpensive.Greece
couldn'taffordto buildone.

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Cable Stayed Bridges:
Thisleftonlyone possibleoption,A Cable StayedBridge.Inthisdesignthere are noexpensive main
cables(unlike SuspensionBridges), insteadthe smallercablesare directlylinkedtothe towers.Itwill be
able to fulfill the demandsof thisBridge.
Main Bridge Concepts:
Pylons
For challengeslike theseBridge made of 3
central spans, 560 m inlengthand2 side
spans,286 m longwasselected. The
correspondingfourpylonsreston large
concrete substructure foundations, 90m in
diameter,65mhigh,whichdistribute all the
forcesto the soil.Below thissubstructure,
the bearingcapacity of the heterogeneous
and weaksoil wasimprovedbymeansof
inclusions, whichconsistof 20mmthick steel
pipes,25 to 30 m longand 2m in diameter,
drivenata regularspacingof 7 or 8m. The
piersare not buriedintothe seabed,but
rather reston a bedof gravel whichwas
meticulouslyleveledtoanevensurface (adifficultendeavoratthisdepth).Duringanearthquake,the
piersshouldbe allowedtomove laterallyonthe seabedwiththe gravelbedabsorbingthe energy.

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Initially,aconcrete blockwhichacts as the base of 4 concrete legs convergingatthe top of the pylons
and givingthemthe appropriate rigiditywassupported bythese huge foundationsthroughoctagonal
pylonshafts,pyramidal capitals andasophisticatedsetof bearingdevices, post-tensionedtendonsand
springdampers. Thiswasabsolutely necessarysince eachpylonsupporteda symmetricalcantilever510
m longand eachcantileverwasconnectedtothe adjacentone or tothe approachesbya simply
supporteddeckgirder50m long.Careful analysesof the behaviorof the reinforcedsoil and
improvementsof thisinnovative conceptledto givingupthe initial staticscheme of the mainbridge and
to adopta muchmore efficientstructure withacontinuouspylon (fromseabedtopylonhead) anda
continuousfullysuspendeddeck isolatedasmuchas possible fromthe pylons. Thisallowedthe depthof
the deckand therefore alsothe windeffectsonthe bridge tobe reduced.

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Deck
The deck isa composite steel-concretestructure, 20m wide,consistingof a concrete slab,25 to 35 cm
thick,connected totwinlongitudinal steel I girders, 2,20m high,braced every4m by transverse cross
beams. Itis continuousoveritstotal lengthof 2252 m, withexpansionjointsatboth ends,andisfully
suspendedby8setsof 23 pairsof cables.Inthe longitudinaldirectionthe deckisfree toaccommodate
all movementsdue tothermal and seismicactionsandthe jointsare designed toaccommodate 2,5m
displacements underservice conditionsand movementsof upto 5,0m in an extreme seismicevent. In
the transverse directionitisconnected toeachpylonwith4 hydraulicdampersof 3500 KN capacity each
and a horizontal metallicstrutof 10 000KN capacity. The stay cablesare arranged intwoinclined planes
ina semi-fanconfiguration. Theyare made of 43 to 73 parallel galvanizedstrandsindividuallyprotected
by an HDPE sheath.
Construction and Completion
The leadarchitectwas Berdj Mikaelian.Site preparationanddredgingbeganinJuly1998, and
constructionof the massive supportingpylonsin 2000. With these complete in2003, workbeganon the
trafficdecksand supportingcables.OnMay21, 2004, the mainconstructionwascompleted;only
equipment(sidewalks,railings,etc.) andwaterproofingremainedtobe installed. The bridge wasfinally
inauguratedonAugust7, 2004, a weekbefore the openingof the 2004 SummerOlympics inAthens.The
total cost of the bridge wasabout€ 630,000,000, funded byGreekstate funds.

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Trouble with cable links
On 28 January2005, six monthsafterthe openingof the bridge,one of the cable linksof the bridge
snappedfromthe top of the M3 pylonandcame crashing downonthe deck.Traffic wasimmediately
halted.The firstinvestigationclaimedthata fire hadbrokenouton the top of the M3 pylon,aftera
lightningstrike inone of the cables.The cable wasimmediatelyrestoredandthe bridge re-opened.
Monitoring System
A structural Healthmonitoringsystemwasinstalledduringconstructiononthe bridge.Itisstill inplace
todayand providesa24/7 surveillance of the structure.The systemhasmore than100 sensors,
including
 3D accelerometersonthe deck,pylons,staycables,andonthe groundto characterize wind
movementsandseismictremors
 Straingaugesand loadcellsonthe stay cablesandtheirgussets
 Displacementsensorsonthe expansionjointstomeasure the thermal expansionof the deck
 Water-levelsensorsonthe pylonbasestodetectinfiltration
 Temperature sensorsinthe decktodetectfreezingconditions
 Linearvariable differentialtransducer(LVDT) sensorsonthe staycablesto measure movement
 Load cellsonthe restrainersforrecalibrationinthe eventof anearthquake
 Two weatherstationstomeasure windintensity,direction,airtemperature,andrelative
humidity
One specificelementof the systemis the abilitytodetectandspecificallytreatEarthquake events.

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Records
ThisBridge enteredthe recordbooks:
 It isthe longestcable stayedsuspensionbridgeinthe world.
 It has longestfullysuspendedcontinousdecki.e.2200 meters.
 It has the world’s largestbridge foundationsandthe deepest,sitting60 metersunderthe sea.
Innovative engineeringallowsthe RioAntirioBridgetosurvive wherethe otherdesignswouldfail.It
standsas one of the world’smegabridges.
A beautifulview at night

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Conclusion
The Rio-Antirio Bridge is a major
and impressive link when compared to
other major cable-stayed bridges such
as the second Severn Bridge and even
to the Normandy Bridge. The design
and construction of this $ 750 million
project undertaken under a private
BOT (build-operate-transfer) scheme
could overcome an exceptional combination
of adverse environmental conditions
thanks to the choice of an appropriate
concept and seismic design philosophy.
The pylons are founded directly
on a gravel layer placed on the
sea bed allowing them to undergo controlled
displacements under the most
severe earthquake and, based on an innovative
concept, the top 20 m of soil
located under the large diameter bases
(90 m) of the pylons are reinforced by
means of steel inclusions to resist high
soil-structure interaction loads. The
2252 m long deck of the cable-stayed
bridge is continuous, fully suspended
and therefore isolated as much as possible
from the worst seismic motions.

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Bibliography:
 Wikipedia
 National Geographic Documentary
 Google Images
 http://www.iabse.gr/support/LargeProjectsGreece/Bridges/Rio-Antirrio/